Abstract

Log-based data management systems use storage as if it were an append-only medium, transforming random writes into sequential writes, which delivers significant benefits when logs are persisted on hard disks. Although solid-state drives (SSDs) offer improved random write capabilities, sequential writes continue to be advantageous due to locality and space efficiency. However, the inherent properties of flash-based SSDs induce major disadvantages when used with a random write block interface, causing write amplification, uneven wear, log stacking, and garbage collection overheads. To eliminate these disadvantages, Zoned Namespace (ZNS) SSDs have recently been introduced. They offer increased capacity, reduced write amplification, and open up data placement and garbage collection to the host through zones, which have sequential-write semantics and must be explicitly reset. We explain how the new ZNS Zone Append primitive, which supports pushing fine-grained data placement onto the device, along with our proposal for “Group Append”, which enables sub-block sized appends, could benefit log-structured data management systems. We explore advantages of ZNS SSDs with Zone Append, Group Append, and computational storage in four log-based data management areas: (i) log-based file systems, (ii) LSM trees such as RocksDB, (iii) database systems, and (iv) event logs/shared logs. Furthermore, we propose research directions for each of these data management systems using ZNS SSDs.